Interestingly, in humans it has been reported that the p48 isoform of 2′5′AS (encoded by the OAS1 gene) has pro-apoptotic activity independent of its synthetase activity [38], and that a 2′5′AS-like protein (encoded by the closely-linked OASL gene) responds to virus infection but has no synthetase activity [39, 40]. Here, OAS1 is linked to viral infectious disease.